Abstract: A system and method for fabricating perovskite films for solar cell applications are provided, the system including a housing for use as a vacuum chamber, a substrate stage coupled to the top section of the housing; a first evaporator unit coupled to the bottom section of the housing and configured to generate BX2 (metal halide material) vapor; a second evaporator unit coupled to the housing and configured to generate AX (organic material) vapor; and a flow control unit coupled to the housing for controlling circulation of the AX vapor. The dimensions of the horizontal cross-sectional shape of the first evaporator unit, the dimensions of the horizontal cross-sectional shape of the substrate stage, and the relative position in the horizontal direction between the two horizontal cross-sectional shapes are configured to maximize the overlap between the two horizontal cross-sectional shapes.

Abstract: A method for fabricating a perovskite film includes the steps of: placing a substrate on a substrate stage in a chamber, the substrate stage configured to rotate around its central axis at a rotation speed; depositing first source materials on the substrate from a first set of evaporation units, each coupled to the side section or the bottom section of the chamber; depositing second source materials on the substrate from a second set of evaporation units coupled to the bottom section, wherein the chamber includes a shield defining two or more zones having respective horizontal cross-sectional areas, which are open and facing the substrate, designated for the two or more evaporation units in the second set. The perovskite film includes multiple unit layers each being formed by one rotation of the substrate stage, and having composition and thickness thereof controlled by adjusting evaporation rates, rotation speed and horizontal cross-sectional areas.

Abstract: Systems and methods for performing a rapid hybrid chemical vapor deposition are described herein. In an embodiment, first type of precursor materials is deposited on a substrate. The substrate is placed in a receptacle of a heating device, the heating device configured to provide heat to at least a portion of the receptacle. A second type of precursor materials is placed in the receptacle of the heating device such that the organic compound is closer to a gas source of the heating device than the substrate. A gas flow is created through the receptacle of the heating device. The heating component is used to cause of a portion of the receptacle comprising the substrate and the second type of precursor materials. During the heating process, at least a portion of the second type of precursor materials is deposited on at least a portion of the first type of precursor materials on the substrate.

Abstract: A method of nanoscale patterning is disclosed. The method comprises: mixing predetermined amounts of a first solvent and a second solvent to generate a solvent, the first solvent and the second solvent being immiscible with each other; dissolving a solute material in the solvent to generate a coating material, the solute material having solubility that is higher in the first solvent than in the second solvent; and applying the coating material onto a substrate to form a plurality of pinholes in the coating material. The formation of the plurality of pinholes is associated with suspension drops mostly comprised of the second solvent, separated from the solute material dissolved in the first solvent, in the coating material. A method of making a stamp with a nanoscale pattern is also disclosed based on the above method.

Abstract: A system and method for fabricating a perovskite film is provided, the system including a housing for use as a CVD furnace having first and second sections coupled with first and second temperature control units, respectively. The first and second sections correspond substantially to the upstream and downstream of gases, respectively. One or more substrates are loaded in the second section and controlled by the second temperature control unit, and an evaporation unit containing an organic halide material is loaded in the first section and controlled by the first temperature control unit. Each of the substrates is pre-deposited with a metal halide material. The inside of the housing is pumped down to a low pressure.

Abstract: A system and method for assessing performance of a plurality of perovskite optoelectronic devices are disclosed. The system comprises a chamber, a light source, a switch board for allowing selection of a device among a plurality of devices in the chamber for measurement; a DC voltage supply for applying voltage to the device, a source/measure unit (SMU) for measuring current of the device; and a computer implemented with a software program including computer executable instructions to control at least the SMU, the DC voltage supply, the switch board, and the light source. The computer-implemented method for the performance assessment by using the system includes obtaining at least one of first current-versus-voltage (I-V) data according to a first procedure and second I-V data according to a second procedure for analyzing hysteresis behavior of the device.

Abstract: A method of forming a Pb-free perovskite film is provided, the method based on vacuum evaporation and comprising: first depositing a first material comprising Sn halide on a substrate to form a first layer; second depositing a second material comprising organic halide to form a second layer on the first layer to obtain a sequentially-deposited two-layer film on the substrate; and annealing the sequentially-deposited two-layer film on the substrate. During the annealing, the first and second materials inter-diffuse and react to form the Pb-free perovskite film. The second layer is formed to cover the first layer so as to prevent the first layer from air exposure. The solar cell device including the Pb-free perovskite film formed by using the present method exhibits good stability.

Abstract: A method of fabricating a perovskite-based optoelectronic device is provided, the method comprising: forming an active layer comprising organometal halide perovskite; making a solution comprising a hole transport material (HTM) and a solvent, the solvent having a boiling point lower than that of chlorobenzene; and forming a hole transport layer (HTL) by spin-coating the solution on the active layer. The solvents having a boiling point lower than that of chlorobenzene include chloroform and dichloromethane.

Abstract: A system and method for fabricating perovskite films for solar cell applications are provided, the system including a housing for use as a vacuum chamber, a substrate stage coupled to the top section of the housing; a first evaporator unit coupled to the bottom section of the housing and configured to generate BX2 (metal halide material) vapor; a second evaporator unit coupled to the housing and configured to generate AX (organic material) vapor; and a flow control unit coupled to the housing for controlling circulation of the AX vapor. The dimensions of the horizontal cross-sectional shape of the first evaporator unit, the dimensions of the horizontal cross-sectional shape of the substrate stage, and the relative position in the horizontal direction between the two horizontal cross-sectional shapes are configured to maximize the overlap between the two horizontal cross-sectional shapes.

Abstract: A system and method for fabricating a perovskite film is provided, the system including a substrate stage configured to rotate around its central axis at a rotation speed, a first set of evaporation units, each coupled to the side section or the bottom section of the chamber, a second set of evaporation units coupled to the bottom section, and a shield defining two or more zones having respective horizontal cross-sectional areas, which are open and facing the substrate, designated for the two or more evaporation units in the second set. The resultant perovskite film includes multiple unit layers, wherein each unit layer is formed by one rotation of the substrate stage, and the composition and thickness of the unit layer are controlled by adjusting at least the evaporation rates, the rotation speed and the horizontal cross-sectional areas.

Abstract: A method of forming a perovskite film is provided, the method comprising inducing a chemical reaction between a metal halide compound and methylamine (CH3NH2) gas. Specifically, the method includes: forming a metal halide film on a substrate; and exposing the metal halide film to the methylamine (CH3NH2) gas for inducing the chemical reaction between the metal halide compound and the methylamine (CH3NH2) gas to form a perovskite film. Post treatments can be carried out by adding a step of exposing the perovskite film to hydriodic acid (HI) gas and methylamine (CH3NH2) gas sequentially or simultaneously.

Abstract: A system and method for assessing performance of a plurality of perovskite optoelectronic devices are disclosed. The system comprises a chamber, a light source, a switch board for allowing selection of a device among a plurality of devices in the chamber for measurement; a DC voltage supply for applying voltage to the device, a source/measure unit (SMU) for measuring current of the device; and a computer implemented with a software program including computer executable instructions to control at least the SMU, the DC voltage supply, the switch board, and the light source. The computer-implemented method for the performance assessment by using the system includes obtaining at least one of first current-versus-voltage (I-V) data according to a first procedure and second I-V data according to a second procedure for analyzing hysteresis behavior of the device.

Abstract: A method of nanoscale patterning is disclosed. The method comprises: mixing predetermined amounts of a first solvent and a second solvent to generate a solvent, the first solvent and the second solvent being immiscible with each other; dissolving a solute material in the solvent to generate a coating material, the solute material having solubility that is higher in the first solvent than in the second solvent; and applying the coating material onto a substrate to form a plurality of pinholes in the coating material. The formation of the plurality of pinholes is associated with suspension drops mostly comprised of the second solvent, separated from the solute material dissolved in the first solvent, in the coating material. A method of making a stamp with a nanoscale pattern is also disclosed based on the above method.

Abstract: An optoelectronic device is provided, the device comprising an active layer comprising organometal halide perovskite and a hole transport layer (HTL) formed by vacuum evaporation and configured to transport hole carriers. The HTL includes a first sublayer comprising a hole transport material (HTM) doped with an n-dopant and disposed adjacent to the active layer, a second sublayer comprising the HTM that is undoped and disposed adjacent to the first sublayer, and a third sublayer comprising the HTM doped with a p-dopant and disposed adjacent to the second sublayer. The doping concentration of the n-dopant for the n-doped sublayer is determined to match the highest occupied molecular orbital energy level of the n-doped sublayer with the valence band maximum energy level of the perovskite active layer.

Abstract: A method of forming a perovskite film is provided, the method comprising inducing a chemical reaction between a metal halide compound and methylamine (CH3NH2) gas. Specifically, the method includes: forming a metal halide film on a substrate; and exposing the metal halide film to the methylamine (CH3NH2) gas for inducing the chemical reaction between the metal halide compound and the methylamine (CH3NH2) gas to form a perovskite film. Post treatments can be carried out by adding a step of exposing the perovskite film to hydriodic acid (HI) gas and methylamine (CH3NH2) gas sequentially or simultaneously.

Abstract: An optoelectronic device is provided, the device comprising an active layer comprising organometal halide perovskite and a hole transport layer (HTL) formed by vacuum evaporation and configured to transport hole carriers. The HTL includes a first sublayer comprising a hole transport material (HTM) doped with an n-dopant and disposed adjacent to the active layer, a second sublayer comprising the HTM that is undoped and disposed adjacent to the first sublayer, and a third sublayer comprising the HTM doped with a p-dopant and disposed adjacent to the second sublayer. The doping concentration of the n-dopant for the n-doped sublayer is determined to match the highest occupied molecular orbital energy level of the n-doped sublayer with the valence band maximum energy level of the perovskite active layer.

Abstract: A method of forming a Pb-free perovskite film is provided, the method based on vacuum evaporation and comprising: first depositing a first material comprising Sn halide on a substrate to form a first layer; second depositing a second material comprising organic halide to form a second layer on the first layer to obtain a sequentially-deposited two-layer film on the substrate; and annealing the sequentially-deposited two-layer film on the substrate. During the annealing, the first and second materials inter-diffuse and react to form the Pb-free perovskite film. The second layer is formed to cover the first layer so as to prevent the first layer from air exposure. The solar cell device including the Pb-free perovskite film formed by using the present method exhibits good stability.

Abstract: A method of fabricating a perovskite-based optoelectronic device is provided, the method comprising: forming an active layer comprising organometal halide perovskite; making a solution comprising a hole transport material (HTM) and a solvent, the solvent having a boiling point lower than that of chlorobenzene; and forming a hole transport layer (HTL) by spin-coating the solution on the active layer. The solvents having a boiling point lower than that of chlorobenzene include chloroform and dichloromethane.

Abstract: An optoelectronic device is provided, the p-doped HTL device comprising an active layer comprising organometal halide perovskite and a hole transport layer (HTL) formed by vacuum evaporation and configured to transport hole carriers. The HTL includes a first sublayer comprising a hole transport material (HTM) doped with an n-dopant and disposed adjacent to the active layer, a second sublayer comprising the HTM that is undoped and disposed adjacent to the first sublayer, and a third sublayer comprising the HTM doped with a p-dopant and disposed adjacent to the second sublayer. The doping concentration of the n-dopant for the n-doped sublayer is determined to match the highest occupied molecular orbital energy level of the n-doped sublayer with the valence band maximum energy level of the perovskite active layer.

Abstract: A system and method for fabricating a perovskite film is provided, the system including a housing for use as a CVD furnace having first and second sections coupled with first and second temperature control units, respectively. The first and second sections correspond substantially to the upstream and downstream of gases, respectively. One or more substrates are loaded in the second section and controlled by the second temperature control unit, and an evaporation unit containing an organic halide material is loaded in the first section and controlled by the first temperature control unit. Each of the substrates is pre-deposited with a metal halide material. The inside of the housing is pumped down to a low pressure.